Pendants are structural work disguised as equipment. What ISO 11197 covers, how the slab fixing and the lamp arm have to be coordinated, how to count outlets, and when a bed head unit is the better answer.
A pendant order placed after the theatre slab is cast is a problem, not a purchase. The arm that reaches over the operating table transmits a substantial moment into the ceiling, the fixing has to go into structure rather than into a suspended ceiling grid, and the position has to miss the surgical light arm through every angle both of them can reach. None of that is negotiable afterwards.
Medical supply units are covered by ISO 11197, which is the standard to name in a specification. What follows is the set of decisions that standard does not make for you.
There are four broad configurations, and the choice is driven by how the clinical team moves around the patient.
Theatres usually take two: an anaesthesia pendant at the head end carrying gases, vacuum and power, and a surgical pendant carrying power, endoscopy services and shelf space for stacks. Intensive care usually takes one, sometimes two where infusion volume is high enough to justify a separate pump column.
An articulated pendant loaded with monitors, gas cylinders, an infusion rack and a stack of endoscopy equipment applies a load at the end of a long lever. The fixing has to be designed for that, and it has to be designed with the slab.
Do not let a pendant be fixed to the suspended ceiling framing. It happens, it looks finished, and it is the single worst thing that can go wrong in a theatre ceiling.
The pendant arms and the surgical light arms share one ceiling and one working volume. The way to resolve this is a reflected ceiling plan with the sweep circle of every arm drawn on it, at the radius the manufacturer states, before anything is ordered. A twin dome light with two long arms on a central mount, for instance, sweeps a large circle over the table, and the anaesthesia pendant has to be outside it at every reachable angle, not just at the parked position.
Also check the vertical order. Light arms and pendant arms at the same height will meet. Where they must cross, one system has to be mounted higher, and that decision affects the ceiling void depth and sometimes the finished floor to ceiling height of the whole theatre.
Count outlets by listing devices, in the same way as for socket outlets at a bed space, and then add margin for the equipment the department will buy in the next five years. Retro fitting an outlet into an installed pendant means taking the head apart.
Three rules apply to what goes inside.
Gas pipeline work itself falls under ISO 7396-1, and the pendant is a terminal of that system rather than a separate one. The pipeline contractor and the pendant supplier must be told they are working on the same system, because when they are not, the joint at the ceiling flange is the one nobody pressure tested.
An articulated arm that drifts out of position is the complaint that arrives six months after handover. Braking is either friction, adjusted mechanically, or pneumatic, released by a button. Pneumatic brakes are pleasant to use and depend on a compressed air or medical air supply staying available, including during a generator transfer. Friction brakes need periodic adjustment and never fail closed. In a hospital with an unreliable air supply, friction is the safer choice even though it demonstrates worse.
Ask what the brake wear part is, whether it is stocked in Bangladesh and what the adjustment procedure is, then make sure that procedure is in the handover training for the biomedical team. Almost every drifting arm in the country is an unadjusted brake rather than a broken one.
A wall mounted bed head unit or service rail costs a fraction of a pendant, needs no slab design, and is installed in a day. It is the right answer for general wards, for high dependency bed spaces where the bed always sits against the wall, and for any retrofit where the ceiling cannot be trusted. The trade off is real: the bed cannot be accessed from the head end without moving it, and cables and hoses cross the space between the wall and the bed.
The honest position is that a district hospital equipping twenty ward beds and four critical care beds should put bed head units on the twenty and pendants on the four. Specifying pendants everywhere because they look better in the drawings consumes a budget that the ward needs for beds and mattresses.
Get these signed before the department is handed over. After the first patient, taking a pendant out of service to correct a fixing is an operational decision rather than a snagging item.